The invention relates to a draw spring clamps with two draw springs positioned in mirror-image layout within a housing. Each of these draw springs possesses an attachment leg resting on a current bus as well as a spring leg that is of one piece with it and that is bent together with the attachment leg into a loop. The attachment leg of the pertinent draw springs extends with its end and with the current bus through the clamp window. The two spring legs of the draw springs are positioned facing each other, and are loadable with tension by means of an actuation element that is positioned within a housing of the draw spring clamp into which a tool blade may be inserted for the purpose of providing spring tension along the direction toward the attachment leg when the clamp window is opened. The above-mentioned actuation element is located between the two opposing spring legs, and also rests in its tensioning position against both spring legs, and also possesses a corresponding rest position on opposing exterior sides for the spring legs of both draw springs.
This type of draw spring clamp is known generally. According to such devices, the actuation element is formed as an oval, rotatable body that correspondingly possesses a maximum diameter and a minimum diameter. In the rotational position of the actuation element at which the maximum diameter is located within the symmetry plane of the draw springs, their spring legs are not tensioned. In the position rotated by 90? in which the maximum diameter of the actuation element is perpendicular to the symmetry plane of the draw springs, their spring legs are tensioned with force and correspondingly are deflected toward each attachment leg of the draw spring, whereby the clamp windows of both draw springs are open. The actuation element includes an insertion slot for a screwdriver blade so that it may be rotated. This involves not only the rotation of the actuation element the rotational position to load the spring legs of the draw springs, from which rotational position the actuation element must be reset by means of a screwdriver blade.
Another type of draw spring is known wherein the actuation element is formed as a slider that may move along a guide formed by the clamp housing. This actuation element assumes an initial position in which it is located between the two opposing spring legs of the draw springs. From this initial position, it may be displaced to the one side toward the first draw spring, and to the other side toward the second draw spring, in order to tension the spring leg of the pertinent draw spring and to open the clamp window of the draw spring. Thus, the two clamp windows of the draw springs may be opened only sequentially.
A draw spring clamp of yet another type is known whereby two pivotable actuation pressers are present to tension the spring legs of the two draw springs that include pressure jaws into which engagement may occur using a screwdriver blade. These actuation pressers are formed as levers with unequal arms, whereby the presser jaw is located on the one lever arm to tension the spring leg of the pertinent draw spring. With this type of device, the clamp positions may also only be serviced sequentially, whereby here even the tool between the actuation pressers must be reset.
Draw spring, clamps of the above-mentioned type are particularly used as plug-in modules. Each of the two draw springs of the clamp hereby receives one of the two connection cables of a cabled module or the like.